The rally, organised by the Irish Congress of Trade Unions (ICTU), was taking place at around 3pm when some of those involved in an earlier flag protest waved an Israeli flag, sparking the confrontation.

Several men tried to pull the Israeli flag from the grasp of a woman holding it. Police separated the two groups.

No arrests were made.

In Londonderry more than a thousand people linked arms on the city's Peace Bridge in a show of solidarity with the people of Gaza.

Meanwhile, thousands of people marched through central London to call for an end to Israel's ground campaign and air strikes in Gaza and other demonstrations took place at locations across the globe.

SDLP leader Dr Alasdair McDonnell has called on the international community to respond to the growing humanitarian crisis.

"The world has witnessed the ongoing mass murder of Palestinian civilians in the latest series of Israeli air strikes in Gaza," Dr McDonnell said.

"The utter disregard for human life must be condemned and every effort employed to put an end to the bloodshed.

"This latest bombardment of the people of Gaza shows a total disregard for both the Geneva Convention and international law."

Dr McDonnell said Hamas' "indiscriminate firing of rockets into Israel is wrong and must stop", and said that this was "no justification whatsoever for the murder of hundreds of civilians".